Sustainable Construction

PIONEER
HILL HOUSE
A Pioneer is defined as one who opens up new
areas of thought, innovation, or development. It is
appropriate that Dyonne Davidson’s newly constructed
home (2011) is located on Pioneer Hill. Dyonne, who
is architecturally trained, has constructed a unique
house showcasing chic modern style, coupled with
the latest in sustainable construction and innovative
technologies. Hopefully, the Pioneer Hill House will
serve as inspiration for those interested in passive
design, active solar heating technologies, water and
energy conservation, heat recovery ventilation, lowVOC materials, unconventional framing techniques,
and Faswall® insulated concrete form construction.
DOUBLE AND STAGGER
STUDDED WALLS
The goal of double and stagger studded walls is to
increase the thermal resistance value (R-value) of the
wall with a larger insulation volume, and also to prevent
heat gain or loss due to thermal bridging. Thermal
bridging occurs when two materials that are poor
thermal insulators come into contact, allowing heat to
flow through the path created. In a typical studwall,
the studs act as a thermal bridge because there is no
insulation between the interior drywall at the stud and
the exterior sheathing at the stud. By staggering studs,
or by building an insulation gap between the interior
and exterior walls, a thermal break is created greatly
improving the insulative performance of the wall.
RAINSCREEN
Traditional siding systems nailed directly to the
plywood often trap moisture between the materials
causing rot and mold. A rainscreen prevents this. At
the Pioneer Hill House, a rainscreen was created by first
wrapping the sheathing with a waterproof membrane. Next, ¾” x 1” pressure treated plywood strips were
nailed to the sheathing. The siding was attached to these
strips, creating a ¾” air gap between the siding and the
water-proof surface allowing moisture to drain and the
circulation of air to keep the wall dry. The air gap of the
rainscreen also enhances thermal resistance by reducing
thermal bridging between the siding and the framing.
FASWALL® CONSTRUCTION
The first 14 feet of the exterior wall is constructed with Faswall® Insulated Concrete Forms (ICF). These are 24”
long interlocking mortarless form blocks that stack using rebar placed both horizontally and vertically as reinforcement. The form block cores are then filled with concrete. Construction is simple and doesn’t required skilled labor; perfect
for an owner built home such as Dyonne’s. The forms cut with typical carpenter’s tools, and the Faswall® surface
takes screws and nails. Faswall® can be an efficient method of building a reinforced concrete wall with built-in
thermal, acoustical and fire protection.
Faswall® is a hygroscopic product, thereby eliminating moisture buildup in the wall. It is highly alkaline and breathable, especially when combined with a stucco and plaster
finish. These factors combine to be inhospitable to mold growth. There is no fume outgassing, no VOC’s, and is formaldehyde free. The block forms are cast from a wood-concrete mix consisting of 85% mineralized
wood chips from recycled wood and 15% Portland cement and fly ash. A 3” inch mineral
wool or rigid foam insert placed in the block’s hollow core boosts the thermal resistance to
R-26. More importantly, the wall’s substantial thermal mass balances diurnal temperature
swings and significantly reduces the Pioneer House’s heating and cooling costs.
PRODUCTS AND
MANUFACTURERS
PASSIVE DESIGN
The floorplan of the Pioneer Hill House seamlessly integrates form and function. The open, receptive simultaneously
models passive design using the arrangement of rooms, walls, and windows to minimize energy consumption and
maximize comfort for the household.
The South facing windows are triple glazed to prevent heat loss. Overhangs are strategically orientated such that
they provide shade from the hot summer sun while allowing rays from the low winter sun to penetrate helping to warm
the home when most needed.
North facing windows at the top of the staircase not only allow for year-around illumination, but more importantly
can be opened in the summer months to circulate air, passively cooling the living space through physical properties of
stack and cross ventilation.
The floors, walls, windows, and roof have very high thermal resistance ratings (R-value), insulating the home and
maintaining optimum temperature in all seasons. Moreover, the walls and floor have a high thermal mass. Thermal
mass is a concept in building design that describes how the mass of the building provides “inertia” against temperature
fluctuations, sometimes known as the thermal flywheel effect. For example, in the winter, thermal mass of the southern wall absorbs heat from direct sunlight during the day then
the thermal mass continues to keep the interior warm by radiating the stored energy during the night. In the summer
months, the southern wall is shaded by deciduous trees and the windows are opened thus limiting the energy absorption
of the wall. The passive cooling design is so effective; the house does not need electric air-conditioning nor was a system
installed.
ACTIVE SOLAR
SYSTEM
While passive design significantly
improves the efficiency of the house, an
active solar design is required for the long
cold Palouse winters. Eight 4’x10’ solar
thermal panels, installed on the Southern
facing rooftop, heat the domestic hot
water supply and hydronic radiant floor
on main level. The system produces hot
water for domestic consumption demands
and for an estimated 75% of the radiant
floor heating.
An on-demand natural gas water
heater serves as a backup to the active
solar system. However, solar lulls during
extended cloudy and cold periods are
commonly bridged by the immense stored
thermal energy from the two feet deep, 150
ton, sandbed that is located beneath the
polished concrete floor slab. The sand’s
thermal mass acts as a “thermal battery”
for the house. The sandbed is charged
by circulating hot water from the solar
thermal panels through hydronic tubes in
the sand. The sandbed is hyper-insulated
on the bottom and sides restricting the
heat flow to be released upward through
the concrete slab. Late August sunshine is
captured and stored, charging the sand for
Fall and Winter.
Cross ventilation through the 2nd Floor
WATER AND ENERGY CONSERVATION:
Passive solar design coupled with the active solar domestic water and heating systems cut gas and electric bills to
a fraction of equivalently sized households. Utility bills are further reduced by such water saving amenities as dualflush toilets, low-flow aerated faucet heads, and narrow and long (instead of wide) bathtubs. The kitchen showcases an
induction cooktop which is more efficient than ranges using gas or electric by 90% and 30% respectively. Moreover,
the selection of Energy Star rated appliances, such as the refrigerator, dishwater, and washing machine, contribute to
additional energy and water savings. Energy Star is the trusted, government-backed symbol for energy efficiency with
the objective of helping consumers save money and protect the environment through energy-efficient products and
practices.
VENTILATION:
In buildings with very tightly insulated building
envelopes such as the Pioneer Hill House, ventilation is
imperative for both comfort and health reasons. Windows
in the Pioneer Hill House have been strategically located
to both cool the interior and provide natural cross
ventilation in warm weather. In colder months, the
house relies on a heat recovery ventilation (HRV) whole
house fan that not only filters the air, but also serves as
a source for significant energy conservation by using the
outgoing stale warm air to warm the incoming cool fresh
air through an enthalpy energy recovery core. The air
exchanger is about 60% efficient meaning it takes 60%
less energy to maintain the preferred temperature in the
house in comparison to a traditional ventilation system.
HEALTHY INDOOR AIR QUALITY:
Indoor air is three times more polluted than outdoor air, and according to the Environmental Protection Agency
(EPA), is considered one of the top 5 hazards to human health. Paints and finishes are among the leading causes of
indoor pollution because they release low level toxic emissions called volatile organic compounds (VOC’s) into the air
for years after application. VOC’s were essential to the performance of the paint until recently when new environmental
regulations and consumer demand led to the development of low-VOC and zero-VOC paints and finishes. Most paint
manufacturers now produce one or more non-VOC variety of paint. These new paints are durable, cost-effective and
less harmful to people and the environment. The interior walls of the Pioneer Hill House are finished with low-VOC
paint, the plaster used to cover the Faswall® is composed of natural compounds, and all cabinetry and wood trim was
selected to be formaldehyde-free.